Technical Capacitance Limit Detection Information TI 127F/00/en nivotester FTC 420/421/422 Limit switches in Minipac design for liquids and bulk solids Application Nivotester FTC 420...422 capacitive limit switches can be used for a variety of purposes, e.g., for: • overspill protection, • inventory monitoring, • interface layer detection, • pump protection, • constant level monitoring and • material flow optimisation. When used with a suitable probe, the Nivotester allows level detection: • in aggressive materials, • at high pressures or in vacuum, • at high or low temperatures, • in coarse- or fine-grained bulk goods, • in high or low viscosity liquids, • in materials with a tendency to form deposits at the probe. Features • Proven 3-wire cabling technique gives interference-free transmission from probe to limit switch. • Calibration from switch cabinet or control room. • Operates in minimum or maximum level failsafe mode. • Operational status of unit and level Nivotester FTC 420: switch indicated by LEDs on front basic version panel. Nivotester FTC 421: • Potential-free change-over contact with adjustable switching delay allows connection of alarms, relays, Nivotester FTC 422: contactors, solenoid valves etc.. with adjustable switching differential • Removable terminal blocks for quick for two-point control connection. Endress+Hauser Nothing beats know-how Function Measuring System The probe and container act as a A bridge on the terminal block sets the capacitor, the capacitance of which is the output relay to act in minimum or dependent upon the level of liquid or maximum fail-safe mode. solids present. The electronic insert, usually mounted in the probe head, The switching status of the relay is passes a level-proportional voltage indicated at the front panel by a red, the signal to the Nivotester for evaluation. operational status by a green LED. On This actuates the output relay when the power failure both LEDs extinguish – the preset level is violated. The resulting output relay de-energises. signal can be used to drive an annunciator, actuator or further relay. FTC 420 FTC 421 FTC 422 e.g. Max. e.g. 2 Max. A typical measuring system comprises: • the Nivotester FTC 420, 421 or 422, • the EC 61 Z e.g. electronic insert and Min. • a probe, suitable for the medium to be measured (for FTC 422 one � or two � for two-point control). 2 Mounting Spacing Installation The Nivotester limit switches use The units can be mounted flush to each Minipac housings with snap-on other provided the operating fastenings suitable for switch cabinet temperature does not exceed 50 °C. For installation on a symmetrical (top hat) ambient temperatures of 60 °C, a gap of rail. 10 mm must be left between adjacent units. The vertical spacing must exceed 15 mm. Protective Housing IP 55 A protective housing with transparent cover, accommodating two units, is available for field installation. Row-mounting on a top hat rail Protective housing IP 55 • A bridge can be inserted between Electrical Connection terminals 1 and 2 of the electronic The Nivotester and electronic insert are insert when there is a tendency for connected by a 3-wire screened conductive build-up to form on the installation cable: two wires supply probe. direct current to the insert, the third • The fail-safe mode is controlled by a carries a voltage signal (3…12 V) bridge between terminals 12 and 13. • proportional to the capacitance of the The potential-free change-over probe back to the unit. contact is located at terminals 4, 5 and 6. The evaluation circuit is isolated from the power supply by a transformer and from the output circuit by a potential-free relay. With bridge: Max.-fail-safe mode Without: Min.-fail-safe mode Bridge for build-up Nivotester at probe (FTC420, FTC 420/421/422 Second probe for FTC 421) or Nivotester FTC 422 two-point control Coaxial cable Shielding When the Nivotester FTC 422 is used with Output relay two probes, the second probe is used without electronic insert and the connection is made Core between probe ground Power supply and core via a coaxial cable. Terminals 1 and 2 of the insert are short-circuited. 3 Mechanical Technical Data • Housing: Minipac housing in light grey plastic, front panel blue. Protection: IP 40 • Dimensions (l x b x h): 113 mm x 50 mm x 75 mm • Weight: approx. 0.3 kg. • Mounting rail: EN 50022-35x15 or EN 50022-35x7.5 Ambient Temperature • Permissible temperature: –20…+60 °C (single instrument), Top hat rail –20…+50 °C (multiple instruments), –25…+80 °C (storage). Dimensions for cabinet mounting [mm] Electrical Connection Outputs • • Terminals: Removable terminal block, Output signal: Potential-free black, 1 x 6-pole, 1 x 7-pole, change-over contact, selectable Protection: IP 20. maximum or minimum fail-safe mode. • • Wire cross-section: Switching capacity: 2 2 1 x 0.5 mm to 1 x 2.5 mm or max. 250 V a.c., max 6 A, 2 2 max. 1500 VA, cos ϕ = 1 2 x 0.5 mm to 2 x 1.5 mm . • Without terminals: Flat plug 0.8 x 6.3 max. 750 VA, cos ϕ ≥ 0.7, as per DIN 46244. max. 250 V d.c., max.6 A, max. 200 W. • • Power supply: Operational display: Green LED lights. 200 V…240 V 50/60 Hz +15 % -10 % 100 V…127 V 50/60 Hz +15 % -10 % • Relay switching status: CE Mark 42 V… 48 V 50/60 Hz ±15 % Red LED lights when de-energised. • 24 V 50/60 Hz ±15 % Response time: 0.2 s, The device fulfils the legal 20 V… 30 V d.c. for FTC 421 adjustable 0…20 s. requirements of the following EC • • Short-out time on power failure: Power consumption: ca. 3 W (4 VA). Guidelines: • Electrical isolation: approx. 0.3 s. Guideline 89/336/EC Transformer between power supply (Electromagnetic compatibility), and evaluation circuit. Guidelines 73/23/EC and 93/68/EC Electronic Insert Relay between evaluation circuit and (Low Voltage Appliances). output circuit. • Housing: Plastic, cast resin electronics, Protection: IP 55. Electromagnetic compatibility (EMC): • Terminals: Protection: IP 00. Immunity to EN 50082-1. • Adjustable Probe Capacitance Connection: 3-core screened cable. Emission to EN 50081-1. • • Permissible ambient temperature: Hook switch –20…+100 °C. Range Capacitance Input voltage For general information on • Frequency: approx. 500 kHz. I ca. 10…100 pF ca. 3…6.6 V electromagnetic compatibility • Power supply: II ca. 80…180 pF ca. 6…8.8 V (test methods, installation hints) III ca. 160…350 pF ca. 8.2…12 V 15 V from Nivotester FTC. see TI 241F/00/e. • Output signal voltage: 3…12 V. • Switching delay for FTC 421: 0…20 s. • Weight: 130 g • Hysteresis for FTC 422: Separate control, ranges as above. Protective Housing for FTC ... • Base: ABS • Front: Impact-resistant plexiglas, matt with transparent window, Protection: IP 55. • Cable glands: 5 x PG 16. • Dimensions (l x b x h): 124 mm x 160 mm x 164 mm. • Weight: 0.5 kg. • Permissible ambient temperature: –20…+50 °C; –20…+40 °C for two units. Subject to modification. EC 61 Z electronic insert. 4 Nivotester FTC 420/421 Nivotester FTC 422 Maximum and This instrument can be set to operate as This instrument provides two-point Minimum Fail-safe a maximum or a minimum limit switch. control with a maximum or minimum For the Nivotester FTC 421 the switch point and a switching differential Mode switching can be delayed by up 20 s, (hysteresis). e.g. to prevent spurious switching due to turbulance etc.. Minimum fail-safe mode The relay de-energises when the product drops below the switch point. Minimum fail-safe mode The relay de-energises when the The red LED lights and remains lit until product drops below the switch point: the switching differential point is the red LED lights. exceeded: the relay energises again. Maximum fail-safe mode: Maximum fail-safe mode: The relay de-energises when the switch The relay de-energises when the switch point is exceeded: the red LED lights point is exceeded. The red LED lights and remains lit until the product drops Power failure below the switching differential point: On a power failure both green and red the relay energises again. LEDs extinguish: the relay de-energises. Power failure On power failure both green and red LEDs extinguish: the relay de-energises. Example for minimum fail-safe mode, FTC 422 Level Relay status LED status green lit Max. Emptying Relay red Min. energised extinguished green lit Max. Relay Min. red lit de-energised green lit Max. Filling Relay Min. red lit de-energised Max. green lit When the Nivotester FTC 422 is used to Relay control the filling or Min. red energised emptying of a vessel, extinguished the red relay status LED indicates that the level is rising or falling. 5 Ordering Information Nivotester FTC 420 Power Supply A 200 VAC ... 240 VAC, 50/60 Hz B 100 VAC ... 127 VAC, 50/60 Hz C 42 VAC ... 48 VAC, 50/60 Hz D 24 VAC, 50/60 Hz E 20 VDC ... 30 VDC. Y Special version, please state FTC 420 N Nivotester FTC 421 Power Supply A 200 VAC ... 240 VAC, 50/60 Hz B 100 VAC ... 127 VAC, 50/60 Hz C 42 VAC ... 48 VAC, 50/60 Hz D 24 VAC, 50/60 Hz E 20 VDC ... 30 VDC. Y Special version, please state FTC 421 Nivotester FTC 422 Power Supply A 200 VAC ... 240 VAC, 50/60 Hz B 100 VAC ... 127 VAC, 50/60 Hz C 42 VAC ... 48 VAC, 50/60 Hz D 24 VAC, 50/60 Hz E 20 VDC ... 30 VDC. Y Special version, please state FTC 422 Electronic Insert EC 61 Z Separate housing for electronic insert Supplementary Technical Information TI 267F/00/en Technical Information TI 228F/00/e Documentation System Components Minipac Technical Information TI 009F/00/e Endress+Hauser GmbH+Co. Instruments International P.O. Box 2222 D-79574 Weil am Rhein Germany Tel. (07621) 975-02 Tx 773926 Fax (07621) 975345 http://www.endress.com Endress+Hauser Nothing beats know-how 10.97/MTM TI 127F/00/en/10.97 EHF/CV4.2